By AUDREY McAVOY
HONOLULU — Hawaii and the federal government are starting a program to reduce the amount of sediment, fertilizer and other pollution that flows into the ocean and harms coral reefs off West Maui.
Coral reefs off Kaanapali and other parts of west Maui have been among the most rapidly deteriorating in the state.
For example, 53 percent of Honolua Bay had coral cover in 1993, but only 8 percent did by 2009. Off Kahekili, coral cover dropped to 30 percent in 2006 from 55 percent in 1993, though it has since recovered slightly to 38 percent.
The $3 million first phase of the program by the Army Corps of Engineers and the state Department of Land and Natural Resources will pay for technical studies to measure the health of coral in the area and help officials better understand what’s causing land-based pollution there.
The studies also will develop ways to address the problem.
“We’re going to be trying to make sure that what we do on land is in fact going to have a beneficial impact to the reefs,” said Russell Sparks of the department’s Division of Aquatic Resources.
The program will address pollution generated across 24,000 acres of Maui, from Kaanapali to Honolua, and from the summit of Puu Kukui to the outer reef.
At the higher elevations, solutions might include restoring and preserving native forests by removing invasive plants and feral animals, and reducing the risk of fire. These efforts should help the forests retain soil and water.
Halfway up the hills, the project likely will focus on restoring streams that are eroding and replanting old agricultural roads that are no longer used. Another important job will be to advise new developments on former agricultural lands so they build in a way that minimizes sediment and pollution runoff.
Part of the problem now is that water runs off old plantation roads down into the sea, instead of being absorbed in the soil.
In cities and towns, older housing and business developments don’t use technology to trap pollutants in storm water, so the pollutants drain into the ocean. West Maui’s wastewater winds up on the reef after being pumped into injection wells. The wastewater is treated so it’s safe for humans, but it still has lots of nutrients that can encourage seaweed growth that smothers coral reefs.
“So now we have to try to be more creative to undo some of those problems and better plan for the future,” Sparks said.
The Army Corps of Engineers will cover 75 percent of the initial $3 million cost. The state Department of Land and Natural Resources will pay for the rest.
Land-based pollution and overfishing are the two biggest causes of coral reef degradation.